Evaluation of the Efficiency of Cassava Peel as a Cement Retarder in Oil Well Cementing

Abstract

Cementing around the casing in oil and gas wells provides proper zonal isolation, holds the casing in place and prevents fluid migration. This procedure is an important part of completing the process and well plugging for abandonment. Retarders are one of the most important additives in oil well cementing if the desired pumping time of cementitious slurry is to be achieved. These retarders can be extracted from natural sources or chemically synthesized. However, synthesized retarders can have significant environmental effects. Thus, this study evaluated the efficiency of cassava peel powder as a biocompatible retarder in oil well cementing and its cement slurry properties.

Cement slurry was prepared, and the thickening time and rheology were tested according to API RP 10B2 (2005) procedures. The performance of cassava peel powder as an oil well cementing retarder was tested at various concentrations and temperatures. Its retardation property was compared with those of a commonly used lignosulfonate-based and a synthetic retarder, respectively. The results obtained at various concentrations of the retarders showed that the thickening time for cassava powder at 70Bc was 02hr: 17mins for 0.03% by weight of cement (%bwoc), 02hr: 20mins for 0.06% and 02hrs:32mins for 0.1%bwoc. The results for lignosulfonate-based retarder are 02hr: 19mins for 0.03%, 02hr: 30mins for 0.06% and 03hr: 02mins for 0.1% bwoc. For the synthetic retarder, the results are 02hr: 29mins for 0.03%, 02hr: 31mins for 0.06%, and 02hr: 51 mins for 0.1% bwoc. These results suggest that the retarding ability of cassava peel powder in oil well cementing is much comparable with those of the existing retarders. It was also observed that cassava peel demonstrates a high-performance concentration response without hampering other cement properties.